c#窗体虚线图形验证码设计

/************************窗体验证码背景图形设计及核心代码**********/

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Drawing;
using System.Drawing.Drawing2D;
namespace 验证码
{
    public class ValidCode
    {
        #region Private Fields
        private const double PI = 3.1415926535897932384626433832795;
        private const double PI2 = 6.283185307179586476925286766559;
        //private readonly int _wordsLen = 4;
        private int _len;
        private CodeType _codetype;
        private readonly Single _jianju = (float)18.0;
        private readonly Single _height = (float)24.0;
        private string _checkCode;
        #endregion
        #region Public Property
        public string CheckCode
        {
            get
            {
                return _checkCode;
            }
            set
            {
                _checkCode = value;
            }
        }

        #endregion

        #region Constructors

        /// <summary>
        /// public constructors
        /// </summary>
        /// <param name="len"> 验证码长度 </param>
        /// <param name="ctype"> 验证码类型：字母、数字、字母+ 数字 </param>
        public ValidCode(int len, CodeType ctype)
        {
            this._len = len;
            this._codetype = ctype;
        }

        #endregion

        #region Public Field

        public enum CodeType { Words, Numbers, Characters, Alphas }

        #endregion

        #region Private Methods
        private string GenerateNumbers()
        {
            string strOut = "";
            System.Random random = new Random();
            for (int i = 0; i < _len; i++)
            {
                string num = Convert.ToString(random.Next(10000) % 10);
                strOut += num;
            }
            return strOut.Trim();
        }
        private string GenerateCharacters()
        {

            string strOut = "";

            System.Random random = new Random();

            for (int i = 0; i < _len; i++)
            {

                string num = Convert.ToString((char)(65 + random.Next(10000) % 26));

                strOut += num;

            }

            return strOut.Trim();

        }

        //

        private string GenerateAlphas()
        {

            string strOut = "";

            string num = "";

            System.Random random = new Random();

            for (int i = 0; i < _len; i++)
            {

                if (random.Next(500) % 2 == 0)
                {

                    num = Convert.ToString(random.Next(10000) % 10);

                }

                else
                {

                    num = Convert.ToString((char)(65 + random.Next(10000) % 26));

                }

                strOut += num;

            }

            return strOut.Trim();

        }

        private System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
        {

            System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);

            // 将位图背景填充为白色

            System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp);

            graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), 0, 0, destBmp.Width, destBmp.Height);

            graph.Dispose();

            double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width;

            for (int i = 0; i < destBmp.Width; i++)
            {

                for (int j = 0; j < destBmp.Height; j++)
                {

                    double dx = 0;

                    dx = bXDir ? (PI2 * (double)j) / dBaseAxisLen : (PI2 * (double)i) / dBaseAxisLen;

                    dx += dPhase;

                    double dy = Math.Sin(dx);

                    // 取得当前点的颜色

                    int nOldX = 0, nOldY = 0;

                    nOldX = bXDir ? i + (int)(dy * dMultValue) : i;

                    nOldY = bXDir ? j : j + (int)(dy * dMultValue);

                    System.Drawing.Color color = srcBmp.GetPixel(i, j);

                    if (nOldX >= 0 && nOldX < destBmp.Width

                     && nOldY >= 0 && nOldY < destBmp.Height)
                    {

                        destBmp.SetPixel(nOldX, nOldY, color);

                    }

                }

            }
            return destBmp;
        }

        #endregion

        #region Public Methods
        public Stream CreateCheckCodeImage()
        {
            string checkCode;

            switch (_codetype)
            {

                case CodeType.Alphas:

                    checkCode = GenerateAlphas();
                    break;
                case CodeType.Numbers:
                    checkCode = GenerateNumbers();
                    break;
                case CodeType.Characters:
                    checkCode = GenerateCharacters();
                    break;
                default:
                    checkCode = GenerateAlphas();
                    break;
            }

            this._checkCode = checkCode;
            MemoryStream ms = null;
            //
            if (checkCode == null || checkCode.Trim() == String.Empty)
                return null;
            Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * _jianju)), (int)_height);
            Graphics g = Graphics.FromImage(image);
            try
            {
                Random random = new Random();
                g.Clear(Color.White);

                // 画图片的背景噪音线

                for (int i = 0; i < 18; i++)
                {

                    int x1 = random.Next(image.Width);

                    int x2 = random.Next(image.Width);

                    int y1 = random.Next(image.Height);

                    int y2 = random.Next(image.Height);

                    g.DrawLine(new Pen(Color.FromArgb(random.Next()), 1), x1, y1, x2, y2);

                }

                Font font = new System.Drawing.Font("Times New Roman", 14, System.Drawing.FontStyle.Bold);

                LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);

                if (_codetype != CodeType.Words)
                {

                    for (int i = 0; i < checkCode.Length; i++)
                    {

                        g.DrawString(checkCode.Substring(i, 1), font, brush, 2 + i * _jianju, 1);

                    }

                }
                else
                {

                    g.DrawString(checkCode, font, brush, 2, 2);

                }

                // 画图片的前景噪音点

                for (int i = 0; i < 150; i++)
                {

                    int x = random.Next(image.Width);

                    int y = random.Next(image.Height);

                    image.SetPixel(x, y, Color.FromArgb(random.Next()));

                }

                // 画图片的波形滤镜效果

                if (_codetype != CodeType.Words)
                {

                    image = TwistImage(image, true, 3, 1);

                }

                // 画图片的边框线

                g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);

                ms = new System.IO.MemoryStream();

                image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);

            }

            finally
            {

                g.Dispose();

                image.Dispose();

            }

            return ms;

        }

        #endregion

    }

}

/************************ 验证码窗体设计代码加载**************/

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace 验证码
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            ValidCode validCode = new ValidCode(5, ValidCode.CodeType.Numbers);
            // 图片加载验证码     
            picValidCode.Image = Bitmap.FromStream(validCode.CreateCheckCodeImage());
            lb_validCode.Text = validCode.CheckCode;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (!this.txtValidCode.Text.Equals(lb_validCode.Text))
            {
                MessageBox.Show(" 请输入正确的验证码!", this.Text);
                this.txtValidCode.Focus();
                return;
            }
        }
        /// <summary>
        /// 双击图片重新刷新验证码
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void picValidCode_DoubleClick(object sender, EventArgs e)
        {
            ValidCode validCode = new ValidCode(5, ValidCode.CodeType.Numbers);
            // 图片加载验证码     
            picValidCode.Image = Bitmap.FromStream(validCode.CreateCheckCodeImage());
            lb_validCode.Text = validCode.CheckCode;
        }
    }
}